Clothing for partial protection of the body against biological agents

ABSTRACT

The invention relates to clothing, manufactured by polypropylene and polyethylene, usable as a partial protection of the body, in particular suitable as barrier against biological agents. The clothing provides a very high level of protection against the penetration of liquids and microorganisms, excellent mechanical properties, including tear and abrasion resistance, outstanding softness, drapeability and comfort.

FIELD OF THE INVENTION

The present invention refers to clothing suitable for the protectionagainst biological agents.

PRIOR ART

There are several situations where workers are exposed to infectivebiological agents, that is micro-organisms, including those which havebeen genetically modified, which may be able to provoke infection,allergy or toxicity.

In some situations, e.g. microbiological laboratories andbiotechnological productions, the infective agents are usually wellknown.

In other types of work, the agents the workers are exposed may not beknown and only possible risks can be assessed; this happens, forexample, in agriculture works, waste treatments, in particular hospitalwastes, veterinary laboratories, emergency clean-up.

In all these circustances, protective clothing are necessary to preventthe infective agent from reaching the skin.

Protective clothing can be made by reusable materials as well as bysingle-use materials.

A great many materials and manufacturing technologies have evolved in anattempt to meet the criteria for a safe, effective and confortableprotective barrier.

Concerning reusable materials, from early 20^(th) century until theearly 1970s, several evolving fabrics were used, starting from cottonwoven which, since it is readily permeable, does not possess anyliquid-resistance capability, moving to a polyester and cotton blendedsheeting with improved mechanical properties and then to tightly wovencotton or polyester and cotton blended fabric with a water repellentchemical finish.

In the 1980s, a new generation of textiles was developed such as tightlywoven fabric made of continues filament yarns, in some cases made ofvery fine filaments (microfibers), which can be chemically finished andmay be calendered to enhance liquid penetration resistance.

All the above woven fabrics rely on the interlocking geometry to provideintegrity and protective barrier.

Single-use protective clothes are commonly constructed of nonwovenmaterials, which rely on fiber bonding technologies (thermal, chemicalor physical) to provide integrity and strength.

The basic raw materials are various forms of natural (for example cottonand wood pulp) and synthetic fibers (for example polyester andpolyolefin).

Fabrics can be engineered to achieve desired properties by the use ofparticular fiber types, bonding processes and fabric finishes.

In summary, fibers can be bonded mechanically, by high-velocity waterjets which entangle the fibers (spunlace), thermally, by in-line meltspinning (spunbond), or chemically, by chemical binders (wet laid).Typically, spunbond fabrics are made of polyolefins.

Both reusable and single-use products are often reinforced to enhance orimprove their properties; for particular applications, additionalmaterials are often added (overall or zoned) in the form of additionallayers of materials, coatings, reinforcements or laminates.

In particular, a second layer of fabric is sometimes used to improveresistance to liquid penetration and skid resistance or chemicals areused to provide reinforcements and liquid-proof characteristics.

Various protective clothes obtained by the above processes have beendescribed: for example in EP 0 365 559 B1 (priority GB 8714535).Polyethylene is one of the most used materials, produced in severaltypes for different applications.

Among others, Tyvek brand protective material is a spundbonded olefinmanufactured from very fine continues filaments of high-densitypolyethylene bonded together by heat and pressure.

These materials are described, for example, in EP 850330 and U.S. Pat.No. 4,321,781.

In particular, there are also overalls manufactured by these materials,which possess very high liquid, powder and chemical resistance but arenot so efficient in terms of tear and abrasion resistance as well as interms of drapeability, softness, flexibility and breathability.

All these aspects are as important as the barrier properties consideringthat the barrier materials should be strong enough to withstand thestresses encountered during typical use and that properties related tocomfort are of primary importance in very critical working situations.Consequently there is a continues need of finding new protectiveclothing with improved effectiveness in providing the appropriate levelof protection against the penetration of liquids and microorganisms and,at the same time, in providing other important performance propertiesincluding mechanical resistance and comfort.

SUMMARY

Now we have found new clothings manufactured by polypropylene andpolyethylene usable to protect specific parts of the body, in particularas barrier against biological agents.

The clothings of the present invention are overall, jacket and trouserswhich provide a very high level of protection against the penetration ofliquids and microorganisms, excellent mechanical properties, includingtear and abrasion resistance, outstanding softness, drapeability andcomfort.

DESCRIPTION OF TE INVENTION

The invention relates to novel clothing suitable for the partialprotection of the body against biological agents.

The clothing consists in a layer of nonwoven material in polypropylenelaminated with a polyethylene film, wherein the ratio in unit weigthbetween polypropylene and polyethylene ranges from 70:30 to 50:50,preferably from 65:35 to 55:45.

The clothing is typically made of a layer of nonwoven polypropylene,having thickness ranging between 240 and 270 microns and unit weigthranging between 35 and 45 g/m², laminated with a polyethylene filmhaving thickness ranging between 30 and 70 microns and unit weigthranging between 20 and 30 g/m².

The total thickness of the material is in the range 270-340 micronswhile the unit weigth ranges between 55 and 75 g/m².

In particular, the clothing is preferably made of a layer of nonwovenpolypropylene, having thickness in the range 245-255 microns and unitweigth ranging between 37.5 and 40.0 g/m², laminated with a polyethylenefilm having thickness ranging between 40 and 60 microns and unit weigthranging between 22.5 and 27.5 g/m²; the preferred thickness of theclothing is in the range 285-315 microns while the unit weigth rangesbetween 60.0 and 67.5 g/m².

The inner layer consists in a nonwoven spunbonded material made up ofcontinues filaments of polypropylene.

The inner layer, besides providing a barrier against liquids andmicroorganisms, ensures high drapeability and comfort and, in addition,is physiologically safe and breathable.

The outer layer is made of a microporous polyethylene film with poresize low enough to prevent the passage of liquids and microorganismsbut, at the same time, to allow moisture to pass on a molecular level,so ensuring a good breathability.

The combination of the two materials in the respective forms and in theappropriate ratios, provides a combination of chemical-physicalproperties and of drapeability and comfort never reached with theclothing for partial body until now known.

In particular, the softness of the material, which ensures the highdrapeability and the excellent comfort in any situation, does notnegatively affect the barrier properties against liquids andmicroorganisms, which, on the contrary, turn out to be equivalent orsuperior in comparison to the known materials with higher density.Furthermore, the tear and abrasion resistance are strong enough towithstand the stresses encounterd during any critical condition of use.

The clothing object of the present invention consists in overall, jacketand trousers.

The clothing has been designed to comply with the specific requirementsof the existing rules, in particular to comply with the Directive 686/89CE (Italian D.L.475—Apr. 12, 1992).

Depending on the kind of clothing, the forge ensures only the protectionof specific parts of the body so that the clothing must be worn togetherwith gloves and other protective apparel in order to ensure theprotection of the remaining parts of the body.

In particular, the overall and the jacket of the present invention canbe coupled with the trousers of the present invention.

FIG. 1 illustrates, as an example, the drawing of the overall; on thefront side (1 a), it protects the exposed parts of the body, such as thebase of the neck, the bust, the arm and the legs as far as the knee.

The overall is equipped with rubber bands round the wrists whichperfectly stick to the wrists in order to isolate arms from contact withpotential hazards.

All the joining parts are assembled by heat welding; the seams ensure anhigh barrier, equivalent to the material's one.

The overall is opened on the back side (1 b) to let that easily put onand can then be closed by four rear fastening means, two in the innerside and two on the outer side.

The clothing is fabricated and designed to avoid area which couldirritate or adversely affect the user.

For example, measurements have been specifically carried but on theoverall to evaluate the dressing and the roughness.

The checked overall complies with the safety and healthy requirements ofD.L. n. 475 dated Apr. 12, 1992 and turned out to be conform to theprescriptions of rule EN 340/94 regarding ergonomy.

The clothing is fabricated in several sizes in order to be comfortablefor any worker in any working situation and to prevent the cloth to bedamaged.

For example, the dimensions, in cm, of the different sizes of theoverall comply with the EN 340 rule and are listed in the followingtable, with a tolerance of +/−3%. Size small medium large length 110 120130 thorax circumference 130 134 140 shoulder width 56 59 62 sleeveswidth 58 59 62

The process of manufacture is based on the standard rules formanufacturing protective clothing.

The material is cut and hollow punched, the different parts are selectedon the basis of the different size and are then marked by numbers.

The dimensions of the different parts are then checked and the clothingis manufactured by heat welding the different components.

A label is then applied inside the clothing.

The label, besides the producer's name, contains, among others, themodel name, the standard picture-writing, the size, the “biologicalhazard” picture-writing,

In particular, the clothing is marked in accordance with the EuropeanStandard (CE) for protective clothing against biological agents.

The information for the user are worded clearly and unambiguosly and theCE marking is clearly evident to guarantee the accordance with thefundamental safety and healthy requirements; FIG. 2 shows an example oflabel.

At the end of the manufacturing process, controls are carried out tocheck that all the parts have been correctly assembled and that thesuperimposition of the different layers as well as the composedstructures are in compliance with the operative instructions.

In particular, the seal of the welded area, the marking conformity amdthe marking position are checked.

Finally, in order to protect the cloth until the moment of use, it isfolded, tacked, the information are inserted and the clothing is packed.

The so manufactured clothing is suitable for the protection againstbiological agents as bacteriae, parasites, fungi and viruses.

The clothing is effective against any microorganism, including whosewhich have been genetically modified, cell cultures and humanendoparasites, which may be able to provoke any infection, allergy ortoxicity.

In particular, the clothing is effective against microorganisms that canbe transmitted by blood and body fluids, such as Hepatitis B Virus(HBV), Hepatitis C Virus (HCV), Human Immunodeficiency Viruses (HIV),against the agents responsable for BSE and other TSE, and against theBacillus Anthracis.

The clothing can be used in any situation in which the workers arepossibly exposed to different kind of dangerous substances in variousforms, like liquids, air, aerosols or solids.

Examples of work situations with risk of exposure to infective agentsare the biotechnological productions, the work in health care (includingisolation and post-mortem units), the work in chemical-biological,veterinary and diagnostic laboratories, the work in refuse disposalplants, the activities where there is contact with animals and/orproducts of animal origin.

The clothing may be worn over the usual working clothes and itseffectiveness is guaranteed only if it is correctly worn, fastened andof appropriate size.

Hereinafter the results of some tests, carried out to evaluate thetechnical properties of the overall are reported. Such results have onlyillustrative aim and they do not imply any limitation.

Barrier Properties

The primary performance of a protective clothing is the effectiveness inproviding the appropriate level of protection against the penetration ofmicroorganisms.

Liquids are generally accepted as the most important vector ofmicrobiological transport but other possible vectors include air andaerosols; in addition, also dry penetration of microorganisms promotedby mechanical action may also be possible.

Consequently, an effective microbial barrier must be resistant to bothwet and dry penetration of microorganisms.

A series of tests (tests 1-3) have been carried out to determine thebarrier properties of the overall of the present invention.

Test 1

Resistance to Penetration by Contaminated Liquids Under a HydrostaticPressure

The test measures the resistance of materials to penetration byblood-borne pathogens using a surrogate microbe under conditions ofcontinues liquid contact.

The test is divided in two parts:

-   a) the material is subjected to successive increasing levels of    pressure, using synthetic blood which simulates blood and other body    fluids; penetration of the synthetic blood through the material is    observed visually. Part a) is used as a screening test.-   b) the resistance of the material to penetration by a surrogate    microbe is measured, the surrogate microbe being a microorganism    which acts as simulant for other microorganisms which are pathogenic    to humans.

The synthetic blood simulates body fluids; many factors can affect thewetting and penetration characteristics of body fluids, such as surfacetension, viscosity and polarity of the fluid.

The surface tension range for blood and body fluids (excluding saliva)is approximately 0.042-0.060 N/m.

The surface tension of the simulant is adjiusted to approximate thelower end of this surface tension range, that is 0.042 (+/−0.002) N/m.

The surrogate microbe used in the test is the Phi-X174 Bacteriophage,which is not pathogenic to humans but serves to simulate viruses thatare pathogenic to humans.

It is one of the smallest known viruses, having diameter 0.027 microns,and is similar in size and shape to HCV, the smallest pathogen of bloodwith diameter 0.03 microns. Consequently, the Phi-X174 Bacteriophagealso serves as a surrogate for HBV (0.042 microns) and HIV (0.10microns)

Test Results:

1a) Screening Test-Resistance to Synthetic Blood

This test method covers the determination of the resistance ofprotective material to penetration by biological liquids, usingsynthetic blood at different levels of hydrostatic pressure.

The test is based on ASTM F 1670 and is used as screening test. The testhas been run on three specimens of 75 mm×75 mm, taken at random, at atemperature of 25 (+/−5)° C., with 52% relative humidity and eachpressure is hold for 5 minutes.

The penetration of the synthetic blood through the material has beenobserved visually for each specimen at the different pressures and pass(P) has been recorded in case of absence of penetration while fail (F)has been recorded in case of penetration.

The results were the following: Pressure (Kpa) Specimen 1 Specimen 2Specimen 3 0 P P P 1.75 P P P 3.50 P P P 7.00 P P P 14.00 P P P 20.00 PP P

The test has been repeated with specimens of the heat welded area andthe same results were obtained.

1b) Test Method for Resistance to Penetration by Infective Agents UsingPhi-X174 Bacteriophage

The test is used to measure the resistance of protective materials topenetration by infective agents, using the bacteriophage Phi X-174 as atest system.

The test only applies to materials that pass the screening test a) andis based on ASTM F 1671.

Three 75 mm×75 mm specimens, taken at random from the material, weretested.

The specimens were subjected to a nutrient broth, containing the virus,to which successive pressure levels were applied, for 5 minutes each, ata temperature of 21 (+/−5)° C.

Detection of penetration of the microorganism at each level was carriedout even when liquid penetration was not visible.

The specimen passes the test when the pfu/ml (plaque forming units permilliliter) which penetrate through the specimen at a given pressure are<1; the material passes the test at a given pressure level when allthree specimens pass.

The results were the following: Pressure Specimen 1 Specimen 2 Specimen3 14.00 Kpa 0 pfu/ml 0 pfu/ml 0 pfu/mlTest 2Resistance to Penetration by Biologically Contaminated Aerosols

The test has been carried out by a Perspex box with Collison atomiser.

A solution, containing the microorganism Staphylococcus Aureus ATCC 6538(NCIMB 9518), has been sprayed into the box. Underpressure is used tocollect the droplets of the contaminated aerosol on two membranefilters. One of these filters has been shielded by the protectiveclothing material.

Then filters were removed, microorganisms were extracted and, afterincubation overnigth at 37° C., were counted.

The ratio of bacteriae found on the shielded and the unshielded filterwas used to assess the barrier properties of the protective clothingmaterial. Four specimens (25 mm diameter circles) were tested for 7minutes.

The result in terms of microorganisms penetrated through the materialwas the following: Specimen 1 Specimen 2 Specimen 3 Specimen 4 0% 0% 0%0%Test 3Resistance Against Penetration by Biologically Contaminated Dust

The test is based on EDANA method 190.0-89/'96.

A powder has been contaminated with spores of Bacillus Subtilis ATCC9372 (CIP A4); then it was vibrated through the protective clothingmaterial for 30 minutes.

The number of microorganisms penetrated through the material was countedafter 24 hours incubation at 35° C.

The test was carried out on six, 200 mm×200 mm, specimens, one of whichused as an uncontaminated control.

The results were as follows: Specimen 1 2 3 4 5 Ref. Microorganisms 0 00 0 0 0Mechanical Properties

Other properties are important in order to assess the performances ofthe material, such as the ability to withstand the mechanical stressesencountered during typical use that could damage the material and thatconsequently would negatively affect the barrier performance.

Some tests (tests 4-8) have been carried out to assess the mechanicalproperties of the clothing.

Test 4

Abrasion Resistance

The abrasion resistance was determined using 00 abrasive paper by theMartindale method and a J.Heal apparatus.

Four specimens were tested at 20 (+/−2)° C., 65% relative humidity with9 Kpa pressure until the formation of the first 0.5 mm diameter hole inthe material (assessed by stereomicroscope)

Results are expressed in terms of cycles necessary for the formation ofthe first hole: Specimen 1 2 3 4 Average Cycles 2880 3300 2500 2500 2795

The method classifies the materials in 4 classes, the highestclassification, level 4 (>500 cycles), denoting materials with thehighest abrasion resistance.

Consequently, according to the test, the material of the presentinvention shows the highest resistance to damage during use.

Hereinafter a list of results is reported based on tests run to assessother mechanical properties.

Test 5

Tear Resistance

-   Trapezoidal method—UNI EN ISO 9073/'99-   Tearing strength in longitudinal direction=59.4 (+/−10.1) N-   Tearing strength in transversal direction=35.2 (+/−5.7) N    Test 6    Flex Cracking Resistance-   Method ISO 7854/'84-   The specimens do not show any damage at 10× untill 100.000 cycles    Test 7    Tensile Resistance (Grab Method)-   method UNI EN ISO 13935-2/'01-   specimens: 100×250 mm-   temperature: 20+/−2° C.-   relative humidity: 65%-   average breaking strength=72.2 (+/−4.6) N    Test 8    Puncture Resistance-   Method UNI EN 863/'96-   Puncture resistance=12.4 N    Resistance to Ignition

There are many potential ignition sources in the normal use of theprotective clothing.

All materials will burn if a high-intensity heat source is applied tothem, especially in the presence of high oxygen levels.

A test was run to assess the flame resistance of the clothing of thepresent invention.

Test 9

Flame Resistance

The test is based on EN 1146/'97 method, using a 40 mm high flame, witha temperature of 800 (+/−50)° C., obtained by propane gas and by abunsen according to the EN/532/'94 rule.

Five specimens were assessed without evidence of any post-combustion orpost-incandescence.

Resistance Against Chemicals

The material, during the normal use, may come into contact with chemicalagents such as clinical liquids, skin disinfectants, lubricants, oils.

As these chemicals can damage the material with consequent influence onthe barrier properties, it is of primary importance that the protectiveclothing has an appropriate resistance against chemicals.

A test was carried out using four different liquid chemicals.

Test 10

Resistance to the Penetration of Liquid Chemicals

The test is based on UNI EN 588 method.

Three specimens were tested using four different chemicals, at 20 (+/2)°C., 65% relative humidity, with a flow of 10 ml per 10 (+/−1) secs.Several parameters were assessed and the average values are listedbelow: Penetration (%) Repellence (%) Absorption (%) H₂SO₄ 30% 0 86.48.6 NaOH 10% 0 86.0 10.2 n-heptane 0 78.7 7.0 isopropanol 0 82.1 8.4Resistance of Joining Areas

Finally, considering that the penetration of liquids can be easier inseams, joins and assemblages of protective clothing, a specific waterpenetration test was carried out in the joining areas.

Test 11

Resistance to Water Penetration Under Increasing Hydrostatic Pressure.

The test is based on UNI EN 2081 1/'93 method, using a TEXTTEST FX 3000apparatus and increasing the water pressure at a rate of 60 cm perminute.

The test was carried out at 20+/−2° C. and 65% R.H. with a watertemperature of 20+/−2° C.

The results are expressed in cm H₂O and in Pa necessary to have thepenetration of the third water drop through the material, in the joiningpositions. cm H₂O Pa specimen 1 280 27500 specimen 2 304 29800 specimen3 282 27700 specimen 4 206 20200 specimen 5 266 26100

1. New gown, jacket and trousers, suitable as protective clothingagainst biological agents and exhibiting very high level of protectionagainst the penetration of liquids and microorganisms, mechanicalresistance properties as well as outstanding softness, drapeability andcomfort, characterized in that the material is manufactured by thelamination of an inner layer of non-woven polypropylene with an outerlayer of polyethylene film, the unit weigth ratio between polypropyleneand polyethylene ranging from 70:30 to 50:50.
 2. New gown, jacket andtrousers as claimed in claim 1, characterized in that said ratio in unitweigth between polypropylene and polyethylene ranges from 65:35 to55:45.
 3. New gown, jacket and trousers as claimed in claim 1,characterized in that the thickness of the material ranges between 270and 340 microns and the unit weigth ranges between 50 and 70 g/m². 4.New gown, jacket and trousers as claimed in claim 1, characterized inthat the inner layer of nonwoven polypropylene has thickness rangingbetween 240 and 270 microns and unit weigth ranging between 35 and 45g/m² and the outer polyethylene film has a thickness ranging between 30and 70 microns and unit weigth ranging between 20 and 30 g/m².
 5. Newgown, jacket and trousers as claimed in claim 1, characterized in thatthe thickness of the material ranges between 285 and 315 microns and theunit weigth ranges between 60.0 and 67.5 g/m².
 6. New gown, jacket andtrousers as claimed in claim 1, characterized in that the inner layer ofnonwoven polypropylene has a thickness ranging between 245 and 255microns and unit weigth ranging between 37.5 and 40.0 g/m² and the outerpolyethylene film has a thickness ranging between 40 and 60 microns andunit weigth ranging between 22.5 and 27.5 g/m².
 7. New gown, jacket andtrousers as claimed in claim 1, wherein the joins are made by heatwelding.
 8. Use of gown, jacket and trousers as claimed in claim 1, asprotective clothing against biological agents, that is microorganisms(bacteriae, parasites, fungi, viruses), including those which have beengenetically modified, cell cultures and human endoparasites, which maybe able to provoke any infection, allergy or toxicity.
 9. Use as claimedin claim 8, characterized in that said biological agents aremicroorganisms that can be transmitted by blood and body fluids (HBV,HCV, HIV).
 10. Use as claimed in claim 8, characterized in that saidbiological agents are the agents responsable for BSE and other TSE. 11.Use as claimed in claim 8, wherein the biological agent is the BacillusAnthracis. 12-14. (canceled)